The present invention relates to an arrangement for the switching of devices in motor vehicles such as driving, braking or steering control systems as a function of whether vehicle wheels are equipped with snow chains.
Various control systems in motor vehicles, such as the antilock system or the wheel slip control system, depend on the condition of the driven wheels or the wheels to be braked. This is particularly true when the wheels are equipped with snow chains. Antilock systems (ABS), for example, would have a better braking effect if, when snow chains are in place, the wheel slip threshold values were increased.
In wheel slip control system (ASR), a manually operable switch is provided at the dashboard of the vehicle. By the switching-on of this switch, the threshold values for the braking and engine control can be changed.
When four-wheel or rear-wheel steering is used, a switching is advantageous when snow chains are in place. In rear wheel steering, a problem exists with respect to the dimensioning of the wheel house that depends on the wheel steering angle. In high-efficiency rear wheel steering systems, the wheel house must be enlarged which affects the design of the rear seat bench and of the trunk of the vehicle. If snow chains are also mounted on the wheels, the wheel house would have to be enlarged to an unacceptable degree. To account for this by means of a signal, the functioning range of the rear wheel control, when snow chains are in place, could be limited and as a result, a normally dimensioned wheel house could be maintained. This signal can be generated by means of the known switch. However, when it is forgotten to actuate the switch after the chains have been put in place, or to open the switch again, after the chains have been removed, this may result in a deteriorating braking or starting behavior or in a rubbing of the chains at the wheel house.
It is therefore an objective of the present invention to improve the arrangement for switching of the threshold or limit values so that the presence or absence of snow chains is securely accounted for.
This and other objectives are achieved in the present invention by providing an arrangement for switching driving, braking and control systems in a motor vehicle as a function of the presence of whether snow chains are mounted on the wheels, this arrangement having at least one sensor assigned to a driven wheel. The sensor scans the wheel for the presence of snow chains, and is arranged at an element of the wheel suspension.